#include <reg52.h>
typedef unsigned int u16;
    
void delay_time(u16 ti)
{
	while(ti--)
	{
		;
	}
}
int main()
{
	for(;;)
	{
		P2=0XFE;
		delay_time(50000);
		P2=0XFF;
		delay_time(50000);
	}
	return 0;
}